The wholesale price index is forecast to have risen 11.86 per cent in the 12 months to Oct. 4, having posted a rise of 11.80 per cent in the previous week, according to the median estimate from a Reuters poll of 11 economists.

In early August, the inflation rate was 12.91 per cent, the highest reading since annual numbers in the current data series became available in April 1995. It jumped into double digits after a hike in government-controlled retail fuel prices in June.

Analysts said inflation has probably already peaked, and may now embark on a downtrend, but the base effect was likely to play a key role in the next few weeks.

"Shortages of primary articles at the start of the festival season will also be seen and the import of non-oil articles will play some role," said Rupa Rege Nitsure, chief economist at Bank of Baroda.

However, three of the 10 economists saw inflation slowing further from the previous week and continuing to ease.

"Everything will see a fair bit of decline. There will be some fall in the manufacturing, a small bit in the primary articles as well. The fuel index is also likely to go down," said Saugata Bhattacharya, economist with Axis Bank.

The data is due around 6 p.m. (1230 GMT) on Thursday.

Last month, central bank governor Duvvuri Subbarao said inflation was showing signs of moderating but it was too early to conclude whether this was a trend.